What is double fertilisation ? Describle the process in brief.

Explanation

Double Fertilisation : The process of fusion of male gemete with the female gamete to form the diploid zygote (2n) is known as fertilisation.
The fusion of one male gamete with egg and that of another male gamete with secondary nucleus is called double fertilisation. It is the characteristic feature of only Angiosperms. All angiosperms are characterized by a unique process called "Double-Fertilisation". It was· discovered by S. G. N awaschin (1898) in Lilli um and Fritillaria Species. Double Fertilisation is significant because it involves the use of both the male gametes produced by a pollen grain. This avoids the chances of polyembryony and increases the chances of survival of future plant. It consists of two fusions and results in formation of two products. First fertilisation restores diploidy in the life cycle. Diploid zygote develops into embyro which subsequently develops into new plant. Second fertilisation product, triploid PEN (Primary Endosperm Nucleus) develops to form a nutritive tissue called endosperm for developing embryo.